Let me start by saying that the Y axis belt seems tight enough. When starting up it often will not travel all the way to activate the limit switch. It is a physical binding. You can't force it further. Tearing the bed off and reassembling will solve it for a number of prints. However it gets back to the same situation. Then homing it will cause it to try and go to the limit It just can't... Not sure what is the best thing to look at. Once you get it fixed it works fine for a day or two.